Overshot-grappling tool



June 29, 1965 D. w. OSMUN 3,191,981

OVERSHOT-GRAPPLING TOOL Filed June 27. 1965 United States Patent O 3,191,981 GVERSHT-GRAPPLING '1001i `Dean W. Osmun, Houston, Tex., assigner to Bowen Tools, Inc., a corporation of Texas Filed dune 27, 1963, Ser. No. 290,961

5 IClaims. (Cl. 29d-$6.31)

This invention relates to new and useful improvements An object of the present invention is to provide a new and improved overshot-grappling tool or casing patch having a helix grapple element which is mounted for nonrotative longitudinal sliding movement While eliminating the sliding keyway connections heretofore used.

An important object of this invention is to provide a new and improved tool which may be used as an overshotgrapple or as a casing patch, wherein a helical grapple element is mounted in a body or bowl with the lower end of the graple element secured to the bowl, and with the grapple element constructed so as to prevent any abrupt bending at the area of attachment of the grapple element to the bowl.

A particular object of this invention is to provide a new and improved overshot-grapple tool orcasing patch which has a helical grapple element disposed in an internal helical groove in the tool bowl or body with the lower end of the grapple element weided or otherwise secured to the bowl and with approximately one revolution of the grapple element extending upwardly from the weld having a smooth internal bore so as to allow the casing or pipe entering the grapple element to become engaged thereby without breaking the welded connection.

The preferred embodiment of this invention will be described hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIG. 1 is a vertical sectional view of the tool of this invention in its running-in position prior to engagement with a pipe or casing;

FIG. 2 is a view Similar to FIG. 1, but illustrating the v tool of this invention with the pipe or casing in the engaged or gripped position; and

FIG. 3 is apartial enlarged sectional view illustrating in detail the gripping action by the grapple element of the tool.

In the drawings, the letter A designates generally the overshot-grapple tool or casing patch of this invention which is adapted to be releasably connected to a pipe or casing C. Briefly, the tool A includes a bowl or body 1Q which is adapted to be connected to a pipe string (not shown) through a top sub 12 or a similarconnecting means. A spiral or helical grapple element 14 is disposed in the bowl 10 for gripping engagement with the casing or pipe C when it is rnoved longitudinally into the bore of the element 14 and inl contact with the gripping teeth 15 thereof. As will be explained more in detail hereinafter, the tool A of this invention is constructed so that it engages a pipe, rod or other object in a well with a gripping action so that the pipe or other object so gripped ice may be removed from the Well. In some instances, the tool A of this invention may be used as a casing patch so that it is disposed over the upper end of a portion of the pipe or casing C and left in position for subsequent use in the well in cooperation with the pipe string above the tool A.

Considering the invention more in detail, the bowl 10 has an internal spiral or helical groove 16 formed therein for receiving the spiral or helical grapple element 14. Both the groove 16 and the grapple element 14 have a left hand helical conguration. In cross-section, the groove 16 has a downwardly and inwardly tapered surface 15a and an upper laterally extending shoulder 1Gb.

The grapple element 14 is formed of a resilient spring material, perferably steel, and is provided with an external surface 14a which Yis downwardly and inwardly tapered as viewed in cross-section for wedging the grapple element 14 in gripping contact with the casing C so as to gradually increase such gripping contact and securely hold the casing C within the bowl 10. In the usual case, the upper end 14h of the grapple element 14 is adapted to engage the laterally extending shoulder 16h prior to the insertion of the casing C or other object within the bore of the grapple element 14 (FIG. l).

The teeth 15 on the grapple 14 preferably have an upward inclination as best seen in FIG. 3 of the drawings to assure an effective gripping engagement between the grapple lelement 14 and the casing C or other object when an upward pull is applied to the tool A, asV will be more evident hereinafter.

In the present invention, the lower end 14e of the grapple element 14 is welded or otherwise connected at 22 to the bowl 1@ at the lower end of the helical groove 16 (FIG. l). Also, the lower portion of the grapple element 'rigid connection. The internal diameter of the teeth 15 are preferably slightly less than the external diameter of the casing or other object C which enters the bore of the grapple element 14 so that the casing C or other object is adapted to pass longitudinally upwardly through the bore of the grapple element 14 while the teeth 15 engage therewith. There is a slight radial or outward expansion of the grapple element 14 by reason of the engagement of the teeth 15 with the external surface of the casing C as can be seen by comparing FIGS. 1 and 2 of the drawings. It is to be noted that the upper end 14e of the grapple element 14 is not attached to the bowl 10.l In fact, the grapple element 14 is not attached to the bowl 1t? in any place other than the weld connection 22.

In order to guide the casing C into the bore of the` grapple element 14, av guide sleeve 25 is disposed within the bore of the bowl 11B below the grapple element 14. Preferably, such guide sleeve 25 is welded tothe bowl 10 as indicated at 25a and the lower annular edge is tapered at 19a and 25a so as to assure the proper alignment of the casing C within the bore of the bowl 10 as the tool A is lowered over the casing C in use. The sleeve 25 has an internal diameter which is about the same, or slightly greater than, the bore of the grapple element 14 as best seen in FIG. 1.

When the tool A is used as a casing patch, a resilient seal 3l? formed of rubber or the like of the type disclosed in U.S. Patent 2,659,440 is preferably utilized. Such seal Y 3l) has Sealing lips 31 and 32 which sealngly engage the external surface of the casing C (FIG. 2). A retaining sleeve 34 of steel or similar material is disposed over the seal 30 as shown in FIG. 1 and is held in such position by a shear pin 35 during the running-in of the tool A. When the upper end of the casing C engages the lower end of the sleeve 34, the shear pin 35 is severed and the sleeve 34 moves upwardly to the position shown in FIG. 2 so as to expose the full seal 30 to the external surface of the casing C.

In the use or operation of the tool A of this invention, it is lowered into a well on a pipe or tubing string connected in the usual manner to the top sub 12. Ordinarily, the casing `C or other stuck object which is to be engaged and gripped by the tool A is disposed a substantial distance below the surface of the well. The casing C is guided into the bore of the bowl 1) by the inclined surfaces 10a and 25a and then by the guide sleeve 25.

Since the lower portion 14d of the grapple element 14 has a smooth bore, the casing C passes smoothly through such smooth bore 14d without any appreciable contact or interference. Ultimately, the casing C engages the teeth 15 on the upper portion of the grapple element 14. Since the teeth 15 project upwardly, the casing C slides upwardly across the teeth 15 even though it engages them. As the grapple tool A is lowered downwardly with respect to the casing C, the grapple element 14 passes downwardly over the casing C. When the upper end of the casing C engages the lower edge of the sleeve 34, the pin 35 is sheared, and the sleeve 34 is moved upwardly to the position shown in FIG. 2, at which point, the relative downward movement of the tool A with respect to the casing C is stopped.

Thereafter, in order to increase the effective gripping action of the grapple element 14 with the casing C, the grapple tool A may be lifted upwardly causing the grapple element 14 to wedge by a downward movement along the tapered surface 16a as illustrated in FIG. 3.

If the casing C or other object is to be removed from the well, the upward lifting with the gripple tool A further increases the gripping action and facilitates the removal of the casing C or other object from the well.

If it should become desirable or necessary to remove the grapple tool A from the casing C or other object engaged thereby, the tool A may be released by rotating it to the right and lifting upwardly on the tool A, whereby the entire tool A may be withdrawn from the well, leaving the casing C in the well.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. A well tool adapted to be used as an overshotgrapple or a casing patch, comprising:

(a) a tool bowl adapted to have its upper end connected to a pipe string,

(b) said bowl having a longitudinal bore with an internal helical groove formed therein,

(c) a helical grapple element disposed in said helical groove,

(d) co-acting downwardly and inwardly tapered surfaces on said grapple element and on said helical groove for causing said grapple element to move inwardly as it moves longitudinally downwardly relative to said bowl so as to effect an increasing gripping action on a pipe engaged by the grapple element,

(e) a weld connection attaching the lower end of said grapple element to said bowl,

(f) a lower section of the inner surface of said grapple element extending upwardly from the attaching means being substantially smooth for about one revolution thereof to enable a pipe to pass therethrough, and

(g) an upper section of the inner surface of said grapple element disposed upwardly from said lower section and having pipe-engaging teeth for gripping a pipe disposed within said grapple element.

2. A well tool adapted to be used as an overshotgrapple or a casing patch, comprising:

(a) a tool bowl adapted to have its upper end connected to a pipe string,

(b) said bowl having a longitudinal bore with an internal helical groove formed therein,

(c) a helical grapple element disposed in said helical groove,

(d) co-acting downwardly and inwardly tapered surfaces on said grapple element and on said helical groove for causing said grapple element to move inwardly as it moves longitudinally downwardly relative to said bowl so as to effect an increasing gripping action on a pipe engaged by the grapple element,

(e) means attaching the lower end of said grapple element to said bowl,

(f) said grapple element having about one revolution of its inner surface formed with a smooth bore to enable a pipe to pass therethrough, and

(g) said grapple element having pipe-engaging teeth formed on its inner surface above the smooth portion for gripping a pipe disposed within the grapple element.

3. A well tool adapted to be used as an overshotgrapple or a casing patch, comprising:

(a) a tool bowl adapted to have its upper end connected to a pipe string,

(b) said bowl having a longitudinal bore with an internal helical groove formed therein,

(c) .a helical grapple element disposed in said helical groove,

(d) co-acting downwardly and inwardly tapered surfaces on said grapple element and on said helical groove for causing said grapple element to move inwardly as it moves longitudinally downwardly relative to said bowl soV as to effect an increasing gripping action on a pipe engaged by the grapple element, and

(e) a weld connection at the lower end of the grapple element connecting the grapple element to the bowl to prevent relative rotational and longitudinal movement therebetween while the portion of the grapple element above the weld connection which is unconnected to the bowl moves longitudinally relative to the bowl.

4. A well tool adapted to be used as an overshotgrapple or a casing patch, comprising:

(a) -a tool bowl adapted to have its upper end connected to a pipe string,

(b) said bowl having a longitudinal bore with an internal helical groove formed therein,

(c) a helical grapple element disposed in said helical groove,

(d) co-acting downwardly and inwardly tapered surfaces on said grapple clement and on said helical groove for causing said grapple element to move inwardly as it moves longitudinally downwardly relative to said bowl so as to effect an increasing gripping action on a pipe engaged by the grapple element,

(e) a weld connection connecting the lower end of the grapple element to the bowl,

(f) a lower section of the inner surface of said grapple element extending upwardly from the attaching means being substantially smooth to enable a pipe to pass therethrough, and

(g) an upper section of the inner surface of said grapple element disposed upwardly from said lower section and having pipe-engaging teeth for gripping a pipe disposed within said grapple element.

5. A well tool adapted to be used as an overshotgrapple or a casing patch, comprising:

(a) a tool bowl adapted to have its upper end connected to a pipe string,

(b) said bowl having a longitudinal bore with an internal helical groove formed therein,

(c) a helical grapple element disposed in said helical groove,

(d) co-acting downwardly and inwardly tapered surfaces on said grapple element and on said helical groove for causing said grapple element to move inwardly as it moves longitudinally downwardly relative to said bowl so as to effect an increasing gripping action on a pipe engaged by the grapple element,

(e) a weld connection attaching the lower end of said grapple element to said bowl,

(f) a lower section of the inner surface of said grapple element extending upwardly from the attaching means being substantially smooth to enable a pipe to pass therethrough,

w(g) an upper section of the inner surface of said References Cited bythe Examiner UNITED STATES PATENTS 5 40,201 5 95 Varney 294-99 2,174,076 9/ 39 Bowen. 2,174,077 9/39 Bowen. 15 2,559,315 7/51 Osmun.

SAMUEL F. COLEMAN, Prmwry Examiner.

ERNEST A. FALLER, Examiner. 

1. A WELL TOOL ADAPTED TO BE USED AS AN OVERSHOTGRAPPLE OR A CASING PATCH, COMPRISING: (A) A TOOL BOWL ADAPTED TO HAVE ITS UPPER END CONNECTED TO A PIPE STRING, (B) SAID BOWL HAVING A LONGITUDINAL BORE WITH AN INTERNAL HELICAL GROOVE FORMED THEREIN, (C) A HELICAL GRAPPLE ELEMENT DISPOSED IN SAID HELICAL GROOVE, (D) CO-ACTING DOWNWARDLY AND INWARDLY TAPERED SURFACES ON SAID GRAPPLE ELEMENT AND ON SAID HELICAL GROOVE FOR CAUSING SAID GRAPPLE ELEMENT TO MOVE INWARDLY AS IT MOVES LONGITUDINALLY DOWNWARDLY RELATIVE TO SAID BOWL SO AS TO EFFECT AN INCREASING GRIPPING ACTION ON A PIPE ENGAGED BY THE GRAPLE ELEMENT, (E) A WELD CONNECTION ATTACHING THE LOWER END OF SAID GRAPPLE ELEMENT TO SAID BOWL, (F) A LOWER SECTION OF THE INNER SURFACE OF SAID GRAPPLE ELEMENT EXTENDING UPWARDLY FROM THE ATTACHING MEANS BEING SUSBTANTIALLY SMOOTH FOR ABOUT ONE REVOLUTION THEREOF TO ENABLE A PIPE TO PASS THERETHROUGH, AND (G) AN UPPER SECTION OF THE INNER SURFACE OF SAID GRAPPLE ELEMENT DISPOSED UPWARDLY FROM SAID LOWER SECTION AND HAVING PIPE-ENGAGING TEETH FOR GRIPPING A PIPE DISPOSED WITHIN SAID GRAPPLE ELEMENT. 